The present invention relates to a solar energy and electric lighting system wherein when the solar energy is available as in the day-time, the conventional electric lamps are lighted by the solar light energy, but when no solar light energy is available or the solar light energy available is not sufficient the electric lamps are electrically turned on. The present invention further relates to solar and electric light lamps which are best adapted for use in the solar energy and electric lighting system described above and which not only may emit the solar energy or the Sun's light transmitted through light guide means but also may electrically produce the light when no solar energy is available.
The solar energy is the cleanest, most abundant and therefore most promising energy source for mankind, but the systems which may efficiently utilize the solar energy in practice have not been developed yet because of the low solar constant. That is, the large solar energy collection device such as a parabolic reflector is needed to increase the energy density, and the collected solar energy is converted into the electrical energy. Alternatively, the solar energy may be collected from a large number of solar cells distributed over a vast area, and the collected solar energy is also converted into electrical energy. However the efficiency of converting the solar energy into electrical energy is very low and the efficiency of the conversion of the electric energy into heat, light, mechanical and other energies is also low. Thus the overall solar energy utilization efficiency is extremely low.